SAINT PAUL, Minn. -- A lot has changed over these past two weeks in the presidential campaign. Labor Day has passed, vice presidential candidates have been picked and both conventions have been held. Senator Obama and Senator McCain have won their party’s nomination marathon, testing their endurance and strategy.

With a little less than two months left in the presidential race, it is time for the middle-distance race. Middle distance combines endurance, speed, strategy and tactics. In a footrace, it’s often thought to be the hardest race because it requires aerobic and anaerobic training, i.e., you have to endure, and be fast.

The final sprint to the finish will begin about two weeks prior to election day.

The selection of vice presidential running mates created a stir and provided insight into their middle-distance strategy. Obama added experience and national security knowledge with the selection of Senator Biden. For those who are not familiar with the Senate, it was created to slow down the process of lawmaking and ensure reflection and deliberation. The Senate is known as an august body that moves slow and talks a lot, and anyone who has listened to Biden knows that he fits right in.

McCain added youth and executive experience to the GOP ticket with his unexpected selection of 44 year-old Sarah Palin, the governor of Alaska whom McCain called his “soulmate” and fellow reformer. This selection also turned up the volume on the presidential race and promises to make it much more interesting.

Whatever the outcome in November, the increased interest from the American people will be good for our country. The question that each and every voter will have to decide is which candidate will be the best president of our country.

Palin’s speech at the Republican convention was much anticipated, and the McCain campaign had a lot riding on her performance. Not only did she deliver, but as I heard one viewer note, “She knocked it out of the park.”

My favorite moment of the convention? After reading signs being held up in front of her by adoring hockey moms, Palin ad-libbed, professing her love for Hockey moms and noting people say “the difference between a hockey mom and a pit bull? Lipstick.”

Well, she had lipstick on, and delivered her lines with a smile, but she was certainly a pit bull when it came to questioning Obama’s experience.

McCain, not known for his speeches in front of large groups, also delivered during his speech last week. He had help from the supportive crowd. Interrupted by protesters at the beginning, the crowd responded by drowning the protester with chants of “USA! USA! USA!” McCain responded with an admonition to the crowd, “Don’t be diverted by crowd noise and static.” When he was again interrupted, McCain noted, “Americans want us to stop shouting at each other, O.K.?”

The introductory video of McCain related the story of his five years as a prisoner of war in Vietnam. For those who make note that he and his campaign often talk about this experience, bear in mind that there is a good reason. This was the defining event of his life and has framed his life ever since. He was broken by interrogation while he was a prisoner of war. He returned to his cell in despair, but his spirit was buoyed by the prisoner of war in an adjacent cell who urged him to “get up and fight again” for his country. He has been doing just that ever since.

It will be interesting to see if we are going to choose “change we can believe in,” or “country first.” In any event – the middle-distance leg has begun, a part of the race during which neither the single qualities of endurance, speed, strategy or tactics will determine the outcome. Instead, victory will go to the team who can best combine all of them.

Stay tuned – anything can happen.

P.S. MSNBC talk show host Chris Matthews said in February, “I have to tell you…the feeling most people get when they hear Barack Obama’s speech. My, I felt this thrill going up my leg. I mean, I don’t have that too often…..He speaks about America in a way that has nothing to do with politics. It has to do with the feeling we have about our country. And that is an objective assessment.”

Standing in the convention center here in Saint Paul at the end of McCain’s speech, I too felt a thrill, but it was in both legs. And that is an objective assessment.